Turbine engines typically include one or more components that compress an incoming flow of air and deliver the compressed flow of air to a combustor that mixes the compressed flow of air with a pressurized flow of fuel and ignites the mixture to create a flow of combustion gases. Combustors of turbine systems often include a micromixer assembly that typically includes a base nozzle structure in communication with a fuel plenum, an air intake, and numerous mixing tubes forming one or more segmented mixing tube bundles. The base nozzle structure supplies a fuel to the fuel plenum. The fuel exits the fuel plenum and enters the mixing tubes. Air is directed into the mixing tubes through the air intake and mixes with the fuel to create an air/fuel mixture. The air/fuel mixture exits the mixing tubes and enters into a downstream combustion chamber. This flow of combustion gases drives the turbine to produce mechanical work for electrical power generation and the like. A turbine engine may use any of a variety of fuels and may be selected from any of a number of different turbine engines, such as those offered by General Electric Company of Schenectady, N.Y. In some particular embodiments, the micromixer assembly includes a plurality of tubes and at least a first end plate that has a plurality of holes drilled or otherwise cut into it in which a first end of each of the tubes terminates, the plurality of holes in the end plate corresponding in number to the plurality of tubes that are disposed within the apertures thereof.
According to various methods, assembly of micromixer tubes within the plate apertures involves a process for fixing them therein in order to stabilize the assembly and minimize vibration of the tubes within the plate. In some instances, this fixation is achieved by friction welding, and in other instances, by use of a relatively expensive brazing filler, which may include gold and/or nickel. Such processes can be time consuming and expensive, and may not always achieve the desired result. Thus, during operation, vibration of the tube within the plate aperture can lead to wear that can ultimately contribute to metal loss and tube tip failure, which can in turn lead to combustor inefficiency and possible failure.